Network, generic (extended)

U3030 Ignition Output Start

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U3030 points to the start output, the line through which a module energizes the starter relay or passes on a crank request; it should be active for seconds at most. In Tokai Rika's push-button start patents the power supply unit switches the starter relay on together with the ignition relays once brake pedal and button are confirmed, and off as soon as the engine controller reports that the engine has fired. Which unit owns this output varies: on GM's 2012 pickups the engine control module, not the body controller, drives the starter enable relay. A module logs U3030 when the line stays dead although cranking is commanded, leaving the engine unable to crank, or stays live after the command ends, which can keep the starter engaged. No manufacturer documents U3030 publicly; starter relay circuit faults have their own codes, P0615 to P0617.

Likely causes

Faulty start driver in the module, not switching or stuck on
Start control wire open or shorted to ground or voltage
Open or shorted coil in the starter relay loading the output
Weak battery pulling the output level down during cranking

Symptoms

  • Engine does not crank when start is requested
  • Starter keeps running or grinding after the engine has fired
  • Start only on a second or third attempt

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€20–800
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ignition outputstarter relayoutput wiring

Related codes

U3010P0615P0616P0617U302D

References: patents.google.com, patents.google.com, gmupfitter.com.